Question

Edwin Hubble was the first to suggest that the universe is expanding. We can verify his theory by observing the of distant stars and galaxies.

Answer 1

Hey mate!!

Here's the answer

If the universe is expanding, this means that all the distances are getting bigger too- those differences are expanding too. 

This change in the difference between the galaxies can be measured by the redshift of distant stars and galaxies. -this is the correct answer. The Redshift was already discovered by Hubble. 

Hoped this helped happy studying